Naslov
The diatom Cocconeis scutellum Ehrenberg in the karstic estuary (Zrmanja River, eastern Adriatic Sea)

Autori
Caput, Katarina ; Viličić, Damir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proc. Abstracts 12th Hungarian algological meeting, Pecs / Acs, Eva; Kiss, K.T.; Grygorszky, I; Borics, G. - Pečuh : Magyar Algologiai Tarsasag, 2001

Skup
Proc. Abstracts 12th Hungarian algological meeting, Pecs

Mjesto i datum
Pečuh, Mađarska, 15.05.2001. - 18.05.2001

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Periphyton; karstic; estuary; Cocconeis scutellum; Adriatic Sea; Croatia

Sažetak
Periphyton assemblages (algal biofilms) can be important factor for majority of production in shallow, unshaded, coastal aquatic habitats. The karstic river Zrmanja (69 km) discharges into the eastern–central Adriatic Sea, and forms shallow, highly stratified estuary. The distribution of attached diatoms on artificial substrates and those in plankton was analyzed in the upper reach of the estuary in July 2000. The sharp halocline was detected in the 1–1.5 m layer. The brackish layer above the halocline (14 PSU), and marine layer (30-34 PSU) bellow the halocline was detected. Thermic conditions (19 to 24 şC) were characterized by subsurface temperature maximum in the halocline. The extremely low concentrations of nutrients (orthophosphates 0.02-0.06 mmol L-1, nitrates 5.3-7.6 mmol L-1), and high oxygen saturation (80-90%) indicated oligothrophic character of the estuary. The euphotic layer extended to the bottom (4 m deep). The maximum abundance of penatae diatoms (9.6 x 107 cells cm–2) was registered after 16 days of colonization in the upper reach of the estuary. The similar abundance was found after 28 days of colonization. The attached penatae diatom Cocconeis scutellum reached the abundance of 105 cells cm-2 after 16 days, while 3.8 x 105 cells cm-2 after 28 days of colonization, in the brackish layer. The local anthropogenic input of nutrients resulted in the 11% and 15% greater abundance of total attached pennatae diatoms, and C. scutellum, respectively. In plankton, C. scutellum was mostly distributed in the 1-3 m layer (400-6400 cells L-1). The outflowing current above the halocline detached cells from the substrate and transported them down the estuary. The population successively sank and accumulated around the halocline, died in the layer of strong gradient of salinity and continued to sink to the bottom. Due to transport by currents, suspended C. scutellum cells were 30% more abundant at the 6 km downstream station. The population was not detectable in the middle reach of the estuary where salinity increased to 34.51 PSU.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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